Prime Minister David Cameron and Prince Charles joined British families of those killed during 9/11 at a ceremony to mark the tenth anniversary of the terror attacks in London’s Grosvenor Square, while services also took place at Grosvenor Chapel, Westminster Abbey and St Paul’s Cathedral.

US Ambassador to Britain Louis Susman, Prince Charles and Prime Minister David Cameron joined families of the British victims of 9/11 at the September 11 memorial garden in Grosvenor Square (Picture: PA)

Around 30 bereaved families gathered at the remembrance service at the September 11 memorial garden next to the American Embassy, where relatives of those killed read out of the names of the 67 British victims of the attacks and laid a white rose for each of them.

The Duchess of Cornwall, Deputy Prime Minister Nick Clegg, US ambassador to the UK Louis Susman, Dame Judi Dench and London mayor Boris Johnson also attended the ceremony, with Mr Johnson earlier saying of the anniversary: ‘Ten years on from 9/11 we mourn those who lost their lives and we will never forget that more Britons perished in the World Trade Centre â many of them Londoners â than in any previous terrorist atrocity.’

An honour guard attend a memorial service at St Paul’s Cathedral (Picture: PA)

Earlier in the day survivors and relatives of those killed during the attacks on New York and Washington DC gathered at an early morning service of ‘remembrance and reconciliation’ in the Grosvenor Chapel in central London, led by canon Jim Rosenthal.

He told worshippers that the 9/11 attacks knew ‘no race, creed, gender, age or status’, saying: ‘The violence which took place in New York, Pennsylvania and Washington took its toll as nearly 3000 people were killed in less than one hour.

‘Remembering such horrific scenes is not easy. But remembrance is not static – it’s a constantly growing and evolving action which gives us the opportunity to take hold of the past and transform it to reach out with grace, understanding and healing.’

Courtney Cowart was nearly buried alive when the North Tower of the World Trade Centre collapsed (Picture: Getty)

Courtney Cowart, who was nearly buried alive after the collapse of the Twin Towers, told the congregation of her experience returning to the site of the wreckage five days after the attacks.

‘Entering the heart of darkness, I was terrified. We were dwarfed by immense wreckage looming around us. It was a landscape drained of all colour.’

At St Paul’s Cathedral American ambassador to the UK Louis Susman joined families of the dead for a service entitled ‘remembering with hope’, which began with the presentation of the Union Flag, the American flag, the US Marine Corps flag and the firefighters’ memorial standard at the cathedral’s altar.

The Dean of St Paul’s, the Rt Rev Graeme Paul Knowles, told the congregation: ‘We gather in this cathedral today to remember before God all who died in the atrocities in New York, Washington and Pennsylvania 10 years ago and to pray with those whose lives were changed forever that day.

‘We also remember those innocent people who, in our lifetime, have had their lives taken from them through acts of terrorism in the cities of our world.’